When we're making a case for something we believe in or greatly desire, our tendency is to  argue for it until we're blue in the face. We heap point on point until the person (or people) we're trying to convince have no choice but to concede. Or, at least, that's what we think we're doing.

TEDx Talk by Niro Sivanathan, associate professor of organizational behavior at London Business School, reveals something quite different. The opposite, in fact.

Leveraging several examples -- sales pitches from pharmaceutical companies and product displays in home goods stores, among others -- Sivanathan makes it clear that our minds aren't great at weighing the quality of a series of points in an argument meant to sway us. Instead, the stronger points are diluted by the weaker ones, making the overall argument weaker.

Here's an example: Let's say you're making a case to other managers at your company to change the hiring process to include an assessment. You start by citing a source that notes companies requiring candidates to complete skills assessments tend to have lower turnover and more engagement from the employees they hire. You tack on some points about how it's not that hard to put one together and the HR team or managers can review and cut candidates who fail.

If you stick with the first point -- the source citing greater engagement and lower turnover -- you have an argument that's hard to refute. The follow-up points, however, can be interpreted a few different ways. HR team members may loathe the extra work. Managers may bemoan the added time it takes to hire, given the extra step in the hiring process. This would likely make several on your team more likely to vote against the change.

In short, stick to the fewer-further rule. Here are a few easy steps to use this rule as you structure your arguments:

  1. Write out all of the points you've considered in support of your argument.
  2. Rank the points by strength (the ones most likely to sway your audience should be at the top).
  3. Write out all of the details of your first point so it is well explained with ample context and, if appropriate, sources that back it up.
  4. Flesh out your second point with just as much detail -- but hold on to this as backup. Do not use it when you first make your argument. This should only be used as an additional tool of persuasion if your strongest point doesn't hit home.

If you want an argument to stick, pick your strongest point and let it stand. Don't dilute the quality with quantity.